1. Field of the Invention
The present invention relates to a method of forming a decorative panel of molded plastic for use as skirting for a mobile home, exterior covering for bare metal structures or the like. More particularly, the present invention relates to a method of mold construction used in conjunction with a vacuum forming process to produce decorative panels having a realistic appearance.
2. Prior Art
The use of various types of decorative plastic panels for use as mobile home skirting is well known in the prior art. As the popularity of mobile homes increases, many consumers desire an attractive and durable material to conceal the undercarriage of their mobile homes. Metal skirting, such as aluminum or steel, is easily dented and becomes permanently bent during settling. Since plastic is generally inexpensive it is the preferred material used in skirting. However, it is highly undesirable for the material to maintain its original plastic appearance since a great deal of mobile homes are permanently affixed to choice real estate lots.
In the prior art, manufacturers have sought various methods to construct skirting panels having a realistic appearance of stone masonry, brick walls and the like. Thin sheets of vinyl plastic, such as PVC, have been used to obtain a realistic appearance. However, the vinyl will become brittle and crack in lower temperatures and then alternately gets soft and warps during hot summer temperatures. The optimum temperature range for PVC vinyl is between 30.degree. and 90.degree. Fahrenheit. In northern climates damage to the PVC skirting due to frost heaves is quite common.
The following prior art U.S. patents have been uncovered as references:
______________________________________ U.S. Pat. No. Patentee Issue Date ______________________________________ 3,215,763 Buerger November 2, 1965 3,183,289 Leavesley, Jr. May 11, 1965 3,621,625 Medow November 23, 1971 3,755,031 Hoffman et al. August 28, 1973 3,379,812 Yakovou April 23, 1968 3,703,572 Bellasalma November 21, 1972 4,241,554 Infantino December 30, 1980 4,275,540 Keller June 30, 1981 4,001,361 Unruh January 4, 1977 ______________________________________
Other references uncovered are as follows: French Pat. No. 1,146,372, issued November 1957 to Andre DuFour, and Japanese Pat. No. 57-45022, issued March 1982 to Toyota Motors.
A decorative skirting panel system for mobile homes is disclosed in U.S. Pat. No. 4,241,554 to Infantino. An expanded polystyrene is injected or poured into molds to form panels having exterior surfaces simulating masonry. The panels are installed by a V-shaped tongue and groove method.
U.S. Pat. No. 4,275,540 to Keller discloses a plastic panel resembling a free standing brick wall section. An open box mold is used to form the wall comprising four tiers of bricks which are bounded by cap stone sections on the top and bottom of each panel.
Another type of mobile home skirting side panel is disclosed in U.S. Pat. No. 4,001,361 to Unruh. The side panel is formed of a sheet of fused polystyrene beads to have the appearance of a masonry wall.
A method of making a panel is disclosed in U.S. Pat. No. 3,755,031 to Hoffman et al., which is used in structures such as cabinets, housings and the like. A plastic sheet and a thin cloth backing are formed into a laminate. The cloth backing is required to provide a flexible member or hinge to permit folding of the panel which is shipped in a knocked-down or flat condition.
A method of making a mold is disclosed in U.S. Pat. No. 3,215,763 to Buerger for subsequent forming of plastic deck panels used in the construction of small pleasure craft. A wood pattern having a smooth exterior surface is used as the form, which is covered with a thin flexible cover sheet. Any design formed in the gel coat of the Buerger mold is derived from the thin vinyl sheeting, such as "Naugahyde", used as a cover sheet. The fiberglass mold generated in the Buerger patent cannot be used in the high stress and high heat operation of vacuum forming.
The French reference to Andre Dufour discloses a method of fabrication for decorative paneling. A wooden model is placed in a box having a plurality of needles or spikes extending upwardly from its surface. Plaster of paris is used to form the mold having vertical channels formed by the spikes. The mold is placed over a vacuum source and a thin sheet of heated plastic is placed over the mold which is subsequently drawn into the mold. The formed plastic is then filled with sawdust and is then placed on a piece of furniture as a type of motif.
The Japanese reference to Toyota Motor discloses a method of mold preparation for vacuum forming. A pre-shaped wood pattern is first covered with an epoxy resin containing aluminum and then a heat resistant material, which forms a relatively thin mold. The mold is removed and perforated for vacuum forming of PVC plastic sheets. The mold created in the Japanese reference has a relatively short durability of 300 shots.
No prior art reference discloses a method of generating a pan-shaped mold formed from a plurality of fiberglass layers thereby creating a heat-resistant mold capable of withstanding years of vacuum forming. No prior art method teaches a highly detailed mold having a realistic detail on its female side capable of completely reproducing its pattern on a relatively thick sheet of high-impact plastic. No prior art method discloses an assembly-line process resulting in rapid production time and consistent results from panel to panel.